Tantalum is irradiated, generally with protons, for use as a target material. Naturally occurring tantalum having therein tantalum-180 and tantalum-181 is irradiated to form the target materials. After a number of years of decay, depending upon the half-lives of the isotopes, most of the hafnium radioisotopes such as hafnium-172, hafnium-173, hafnium-175 and hafnium-179.sup.m decay away, leaving higher proportionate amounts of hafnium-178.sup.m2. After the tantalum is irradiated for employment as a target material, it is useful to be able to recover the hafnium radioisotopes for a variety of uses including use as precursors for radioactive materials for medical diagnosis and treatment and use for nuclear physics studies, including use in gamma ray lasers.
Traditionally, separation techniques for recovering hafnium isotopes from irradiated tantalum which has been irradiated employ solvent extractions with reagents that are now considered hazardous. The solvent extraction techniques are now considered problematic because solvent extraction techniques generate a mixed-waste stream containing radioactive and hazardous components that cannot easily be treated for disposal.
Therefore, there is a need for methods of recovering hafnium radioisotopes from irradiated tantalum targets without creation of undesirable waste streams.
It is an object of this invention to provide a method for obtaining hafnium radioisotopes from irradiated tantalum.
It is another object of this invention to provide a solvent-free method for recovering hafnium-178.sup.m2 from irradiated tantalum.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. The claims appended hereto are intended to cover all changes and modifications within the spirit and scope thereof.